How to calibrate the parameters of intelligent spinning testing machine?

The parameter calibration of intelligent spinning testing machine should focus on "spinning core index+key parameters of equipment operation" and follow the logic of "single point calibration first, then linkage verification" to ensure that the accuracy of each parameter meets the requirements of spinning process. The following are specific calibration methods and precautions.

1. Calibration of core process parameters (spinning quality is directly related)

These parameters directly affect the quality of filament forming, and need to be accurately calibrated by professional measuring tools, focusing on three dimensions: temperature, speed and flow.

Spinning temperature calibration

Calibration tools: high-precision thermocouple (accuracy 0.1℃) and temperature inspection instrument.

Calibration steps: ① attach the thermocouple probe to the key temperature measuring points such as the heating area of spinning box, the surface of spinneret, melt pipeline, etc., to ensure that the position of the probe is consistent with that of the temperature measuring element of the equipment; (2) Set the target temperature of the equipment (such as 260℃ and 280℃, covering the common process temperature range), and after the temperature is stable, record the temperature of the display screen of the equipment and the measured temperature of the thermocouple; (3) If the deviation is greater than 1℃, adjust it through the temperature compensation function of the equipment control system and test it repeatedly until the deviation is within the allowable range; ④ At least three different temperature values should be calibrated at each temperature measuring point to ensure the accuracy of the whole temperature range reaches the standard.

Spinning speed calibration

Calibration tools: laser velocimeter (accuracy ±0.01m/min) and stopwatch (accuracy ±0.01s).

Calibration steps: ① For the godet roller and the winding roller, firstly clean the roller surface (to avoid the influence of silk scraps on the speed measurement) and align the laser velocimeter with the center line of the roller surface; (2) Set the target speed of the equipment (such as 500m/min and 800m/min, covering the common speed interval), and after the roller body runs stably, record the displayed speed of the equipment and the measured speed of the laser velocimeter; (3) If the deviation is > 0.5%, adjust the frequency converter parameters or motor transmission ratio of the equipment, and use a stopwatch to assist verification after calibration (measure the number of turns of the roller body in one minute, calculate the actual speed in combination with the roller diameter, and compare it with the displayed value of the equipment); ④ It is necessary to calibrate the speed under no-load and load (simulated with wire) respectively to ensure the same accuracy under the two working conditions.

Metering pump flow calibration

Calibration tools: electronic balance (accuracy ±0.01g), stopwatch and beaker.

Calibration steps: ① disconnect the metering pump from the spinneret and connect a beaker at the pump outlet; ② Set the rotating speed of the metering pump (such as 20r/min and 50r/min, covering the common rotating speed), start the pump body to run, and at the same time use a stopwatch to collect the melt within 10 minutes (or simulate fluid, such as silicone oil, which needs to be confirmed in advance to be consistent with the melt density); ③ Weigh the collected fluid quality with an electronic balance, calculate the actual flow (flow = mass/time/density) according to the fluid density, and compare it with the set flow of the equipment; (4) If the deviation is > 1%, adjust the motor speed parameter of the metering pump or check the pump body seal (to avoid internal leakage affecting the flow), repeat the test for 3 times, and take the average value to ensure the calibration accuracy.

Second, the auxiliary operation parameter calibration (equipment stability related)

Such parameters affect the stability of equipment operation, and need to be calibrated one by one in combination with equipment functional modules, focusing on pressure, tension and detection accuracy.

Hydraulic/pneumatic pressure calibration

Calibration tool: precision pressure gauge (accuracy ±0.01MPa).

Calibration steps: ① Turn off the hydraulic/pneumatic system of the equipment and connect the precision pressure gauge in parallel at the interface of the equipment pressure sensor; (2) Start the system, and gradually adjust the pressure to the target value (such as 3MPa for hydraulic system and 0.5MPa for pneumatic system). After the pressure is stabilized, compare the pressure on the display screen of the equipment with the reading of the precision pressure gauge; (3) If the deviation is > 0.02 MPa, the system pressure regulating valve or controller parameters shall be corrected, and the pressure shall be maintained for 30 minutes after calibration to observe whether the pressure is stable (fluctuation range ≤±0.01MPa) to avoid pressure drift caused by leakage.

Wire tension calibration

Calibration tools: tension sensor calibrator (accuracy ±0.1N) and standard weight.

Calibration steps: ① Disconnect the original tension sensor of the equipment and connect the calibrator, or directly hang standard weights (such as 5N and 10N, covering the common tension range) on the tension detection roller; ② Start the tension control system of the equipment, and record the tension value displayed by the equipment and the reading of the calibrator (or the actual weight of the weight); ③ If the deviation is > 0.2n, adjust the amplification factor or zero-point deviation of the tension controller. After calibration, it is necessary to simulate the spinning process and test the responsiveness of tension with speed change (when the speed changes, the tension fluctuation should be ≤±0.5N) to ensure the stability of tension control.

Calibration of filament detection parameters

Calibration tool: standard wire sample (with known diameter and defect type, such as 20μm in diameter and 0.5mm in hairiness defect).

Calibration steps: ① pass the standard sample through the wire detection module (such as laser caliper and defect detector); (2) record the diameter value and defect number detected by the equipment and compare them with the parameters of the standard sample; ③ If the diameter deviation is > 0.001 mm, or the defect miss rate is > 1%, adjust the laser intensity, sampling frequency or algorithm parameters of the detection module, and continuously test 10 groups of standard samples after calibration to ensure the detection accuracy and repeatability meet the standards.

Iii. Verification and recording after calibration

After the calibration is completed, it is necessary to confirm the consistency of parameters through linkage test, and make a good document record to provide a basis for subsequent maintenance.

Linkage verification: Set a complete set of spinning process parameters (such as temperature of 270℃, speed of 600m/min and flow rate of 5g/min), carry out load trial operation for 30 minutes, monitor the fluctuation of each parameter (temperature fluctuation ≤ 0.5℃, speed fluctuation ≤ 0.3%, flow fluctuation ≤ 0.5%) in real time, and observe the yarn quality (diameter uniformity).

Record filing: record the calibration date, calibrator, measuring tools used (including number and calibration validity period), pre-calibration deviation, post-calibration value and adjustment method of each parameter in detail, and form a Parameter Calibration Report; Calibration tools need to be sent to metrological institutions for verification regularly (such as thermocouple once a year and electronic balance once every six months) to ensure the accuracy of the tools themselves.